Research On Low Frequency Rotation Sensor And Its Calibration System

The development of low frequency and ultra low frequency servo vibration sensors for detecting the translational vibration has been quite mature,and the sensors have made great contributions to the research of structural vibration.The vibration monitoring system developed by the Institute of engineering mechanics of China Earthquake Administration has been used in many fields widely,such as earthquake observation,railway bridge,large construction,wind power tower,hydropower station and so on.However,the researches on sensors for measuring the rotational components of earthquakes and structures are still in its infancy,in China.At present,many domestic and foreign scholars have carried out the research on the rotational component of earthquakes and the rotating destruction of structures,but many of these studies are based on theories and the data translated from the translational vibration,so it is urgent to be verified and supported by the data measured by rotational sensors.Therefore,the researches of low frequency rotation sensors and their calibration systems are carried out in this paper.First,the basic principle of the magneto-electric sensor is introduced in this paper,the Laplasse transform method is used to simplify the derivation of the principle,and several inertial pendulum are simulated.According to the basic design methods of the existing passive servo sensor,the low frequency passive servo rotation speed sensor and the passive servo large damping rotational acceleration sensor are studied,the design structure and the basic working principles of these two kinds of sensors are discussed in detail,the frequency characteristics of these sensors are simulated and tested by experiment.The results of simulation and test show that these two sensors are able to measure the low frequency rotational components effectively.Besides,some methods to expand the frequency range of sensors are discussed.Theoretically,the active servo method can expand the low-frequency characteristics of sensors well much.Then,the calibration method of low frequency rotation sensor is studied,the basic principles of several calibration methods are studied in detail.On the basis of the theories,Labview are used to develop the calibration system software of comparison calibration method which is based on low frequency rotating vibration table and self calibration method,and the function of the software are described in detail.Using this software to combine data acquisition card and small low frequency rotating vibrator,a calibration system based on rotating vibration table is formed,the existing RA013 rotational accelerometer is calibrated by this system.In addition,the sensitivity characteristic curve low to 0.05 Hz of this sensor is calibrated in combination with the self calibration.Finally,some problems in the engineering application of sensor are discussed,and a software that can be used for vibration signal acquisition is designed by Labview.The low frequency rotation signal acquisition system is composed of the rotational accelerometer,data acquisition instrument and other instruments,and the low frequency rotation acceleration signal is measured on the offshore platform successfully.At the end of the paper,the summary and prospect of this article are made.